On one hand, I definetely don't mind about color restrictions, I think it's lovely and like how it reads. On  the other, I really think 51 might get confusing if you ever decide you want to have simple palette variations or maybe even when animating. But the design sense is strong, and the pixel placement is tight - great job.

Thank you for the tips! :)

Nice stuff! Another feedback is to watch your palette management, there are 56 unique colors in here when it could easily be done with 16! 
Also, where are the hands? And the eyes are a bit far apart perhaps. 
But still pretty nice :)

Thank you! I also got a copy of Aesprite and that is helping alot! :)

Cute! I like the colors that you used, although it looks like the piece has a lot of near indistinguishable duplicate colors. I'd just advise to try to minimize stray pixels, or pixels that jut out from your clusters. It'll help with the readability, and at this size they can really make a piece noisy. Still, awesome work!